The outcome of revision total hip arthroplasty for instability.

Aims: Instability is a common indication for revision total hip arthroplasty (THA). However, even after the initial revision, some patients continue to have recurrent dislocation. The aim of this study was to assess the risk for recurrent dislocation after revision THA for instability. Methods: Between 2009 and 2019, 163 patients underwent revision THA for instability at Stanford University Medical Center. Of these, 33 (20.2%) required re-revision due to recurrent dislocation. Cox proportional hazard models, with death and re-revision surgery for periprosthetic infection as competing events, were used to analyze the risk factors, including the size and alignment of the components. Paired t-tests or Wilcoxon signed-rank tests were used to assess the outcome using the Veterans RAND 12 (VR-12) physical and VR-12 mental scores, the Harris Hip Score (HHS) pain and function, and the Hip disability and Osteoarthritis Outcome score for Joint Replacement (HOOS, JR). Results: The median follow-up was 3.1 years (interquartile range 2.0 to 5.1). The one-year cumulative incidence of recurrent dislocation after revision was 8.7%, which increased to 18.8% at five years and 31.9% at ten years postoperatively. In multivariable analysis, a high American Society of Anesthesiologists (ASA) grade (hazard ratio (HR) 2.72 (95% confidence interval (CI) 1.13 to 6.60)), BMI between 25 and 30 kg/m2 (HR 4.31 (95% CI 1.52 to 12.27)), the use of specialized liners (HR 5.39 (95% CI 1.97 to 14.79) to 10.55 (95% CI 2.27 to 49.15)), lumbopelvic stiffness (HR 6.03 (95% CI 1.80 to 20.23)), and postoperative abductor weakness (HR 7.48 (95% CI 2.34 to 23.91)) were significant risk factors for recurrent dislocation. Increasing the size of the acetabular component by > 1 mm significantly decreased the risk of dislocation (HR 0.89 (95% CI 0.82 to 0.96)). The VR-12 physical and HHS (pain and function) scores improved significantly at mid term. Conclusion: Patients requiring revision THA for instability are at risk of recurrent dislocation. Higher ASA grades, being overweight, a previous lumbopelvic fusion, the use of specialized liners, and postoperative abductor weakness are significant risk factors.

Primary Total Hip Arthroplasty in Juvenile Idiopathic Arthritis: Survivorship After a Median Follow-Up of 12 Years.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a chronic inflammatory condition of childhood that frequently affects the hip. Total hip arthroplasty (THA) in JIA can be challenging due to the patient's young age, small proportion, complex anatomy, and bone loss. Outcome data are limited. METHODS: We reviewed prospectively collected data in 57 JIA patients (83 hips) who underwent THA between 1986 and 2020 by a single surgeon. The median patient age at surgery was 26 years (range, 14 to 62). Reoperation-free survival was assessed via the cumulative incidence function, accounting for the competing risk of death. Relationships between patient and implant factors and survivorship were evaluated by stratification of the cumulative incidence function and Gray's tests. Wilcoxon signed rank tests were used to assess the preoperative to latest postoperative change in patient-reported outcome measures. RESULTS: At a median (interquartile range) of 12 (4, 20) years of follow-up, 13 (16%) patients underwent reoperation, most commonly for polyethylene wear and osteolysis (7 hips). The estimated incidence of 10-year, 20-year, and 30-year revision (95% confidence interval) were 11.3% (4.5, 21.6%), 18.5% (8.9, 30.9%), and 40.6% (19.4, 60.9%), respectively. There were no differences in survival based on patient age, sex, implant fixation method, polyethylene type, or thickness. All patient-reported outcome measures improved from preoperative to latest follow-up. CONCLUSIONS: Primary THA is a durable and effective treatment for JIA patients with severe hip involvement and results in major improvements in pain and function. We did not identify any factors predictive of failure.

Revision Hip Arthroplasty Using a Modular, Cementless Femoral Stem: Long-Term Follow-Up.

BACKGROUND: As the number of primary total hip arthroplasty (THA) cases increase, so does the demand for revision operations. However, long-term follow-up data for revision THA is lacking. METHODS: A retrospective review was completed of patients who underwent revision THA at a single institution between January 2002 and October 2007 using a cementless modular stem. Patient demographic, clinical, and radiographic data was collected. Preoperative and postoperative patient-reported outcome scores were compared at a minimum of fourteen-year follow-up. RESULTS: Eighty-four patients (89 hips) with a median age of 69 years (range, 28 to 88) at operation were included. Indications for revision included aseptic loosening (84.2%), infection (12.4%), and periprosthetic fracture (3.4%). Twenty-two hips sustained at least 1 complication: intraoperative fracture (7.9%), dislocation (6.7%), prosthetic joint infection (4.5%), deep venous thrombosis (3.4%), and late periprosthetic fracture (2.2%). There were no modular junction complications. Eight patients underwent reoperations; only three involved the stem. Thirty-eight patients (45%) were deceased prior to final follow-up without known reoperations. Twenty-seven patients (32%) were lost to follow-up. Twenty-one patients (23%) were alive at minimum fourteen-year follow-up. Complete patient-reported outcomes were available for nineteen patients (range, 14 to 18.5 years of follow-up). Significant improvement was seen in UCLA activity, VR-12 physical, hip disability and osteoarthritis outcome score, joint replacement., and Harris Hip score pain and function scores. CONCLUSION: Challenges of long-term follow-up include patient migration, an unwillingness to travel for re-examination, medical comorbidities, advanced age, and death. The cementless modular revision stem demonstrated long-term clinical success and remains a safe and reliable option for complex revision operations.

Outcome of the Wagner Cone femoral component for difficult anatomical conditions during total hip arthroplasty.

PURPOSE: Total hip arthroplasty (THA) in patients with small or unusual proximal femoral anatomy is challenging due to sizing issues, control of version, and implant fixation. The Wagner Cone is a monoblock, fluted, tapered stem with successful outcomes for these patients; however, there is limited information on subsidence, a common finding with cementless stems. METHODS: We retrospectively reviewed our cases using the modified Wagner Cone (Zimmer, Warsaw, IN) implanted over a 13-year period (2006-2019) in patients with small or abnormal proximal femoral anatomy. We performed 144 primary THAs in 114 patients using this prosthesis. Mean follow-up was 4.5 ± 3.4 years (range, 1-13 years). Common reasons for implantation were hip dysplasia (52%) and osteoarthritis in patients with small femoral proportions (22%). Analysis of outcomes included assessment of stem subsidence and stability. RESULTS: Survival was 98.6% in aseptic cases; revision-free survival was 97.9%. Femoral subsidence occurred in 84 cases (58%). No subsidence progressed after 3 months. Of those that subsided, the mean distance was 2.8 ± 2.0 mm. There was less subsidence in stems that stabilized prior to six weeks (2.2 ± 1.4 mm) compared to those that continued until 12 weeks (3.9 ± 1.6, p = 0.02). Harris Hip, UCLA, and WOMAC scores significantly improved from pre-operative evaluation (p < 0.001*, p < 0.003*, p ≪ 0.001*); there was no difference in outcome between patients with and without subsidence (p = 0.430, p = 0.228, p = 0.147). CONCLUSION: The modified Wagner Cone demonstrates excellent clinical outcomes in patients with challenging proximal femoral anatomy. Subsidence is minor, stops by 3 months, and does not compromise clinical outcome.

Reconstruction of Disrupted Extensor Mechanism After Total Knee Arthroplasty.

BACKGROUND: Disruption of the extensor mechanism after total knee arthroplasty (TKA) is a debilitating complication that results in extension lag, limited range of motion, difficulty in walking, frequent falls, and chronic pain. This study presents the clinical and radiographic results of reconstruction after extensor mechanism disruption in TKA patients. METHODS: Consecutive patients with allograft reconstruction of extensor mechanism after TKA were identified retrospectively from an academic tertiary center for revision TKA. RESULTS: Sixteen patients with a mean age of 61 ± 14 years at extensor mechanism reconstruction with a minimum of 2-year follow-up were included. The mean follow-up was 3.3 ± 2.2 years. Knee Society score (KSS), before and at final follow-up extension lag, range of motion, and radiographic change in patellar height were reviewed. There were statistically significant improvements between preoperative and final follow-up KSS (P < .001; KSS for pain, preoperative 40 ± 14 points to final follow-up 67 ± 15 points [P < .001]; KSS for function, preoperative 26 ± 21 points to final follow-up 48 ± 25 points [P < .001]). The extension lag was also reduced from 35° ± 16° preoperatively to 14° ± 18° (P < .001) at final follow-up. There was an average proximal patellar migration of 8 ± 10 mm. Five (31%) cases had an extensor lag of >30° or revision surgery for repeat extensor mechanism reconstruction, infection, or arthrodesis. CONCLUSION: Our 10-year experience using allografts during extensor mechanism reconstruction demonstrates reasonable outcomes, but failures are to be anticipated in approximately one-third of patients.

Cortical Strut Allograft Support of Modular Femoral Junctions During Revision Total Hip Arthroplasty.

BACKGROUND: There is risk of junction failure when using modular femoral stems for revision total hip arthroplasty (THA), especially with loss of bone stock in the proximal femur. Using a cortical strut allograft may provide additional support of a modular femoral construct in revision THA. METHODS: We reviewed prospectively gathered clinical and radiographic data for 28 revision THAs performed from 2004 to 2014 using cementless modular femoral components with cortical strut allograft applied to supplement proximal femoral bone loss: 5 (18%) were fluted taper designs and 23 (82%) were porous cylindrical designs All the patients had a Paprosky grade IIIA or greater femoral defect. The mean follow-up was 5.4 ± 3.9 years. RESULTS: The Harris Hip Scores improved from 26 ± 10 points preoperatively to 71 ± 10 points at final follow-up (P < .001). The Western Ontario McMaster Universities Osteoarthritis Index scores improved from 45 ± 12 points preoperatively to 76 ± 12 points at final follow-up (P < .001). Eighty-nine percent (25 hips) of all revision or conversion THAs were in place at final follow-up. Three (11%) patients underwent reoperations, 2 for infection and 1 for periprosthetic fracture. There was no statistical significant change in femoral component alignment (P = .161) at final follow-up. Mean subsidence was 1.8 ± 1.3 mm at final follow-up. Femoral diameter increased from initial postoperative imaging to final follow-up imaging by a mean of 9.1 ± 5.1 mm (P < .001) and cortical width increased by a mean of 4.5 ± 2.2 mm (P < .001). Twenty-seven hips (96%) achieved union between the cortical strut allograft and the host femur. CONCLUSION: The use of a modular femoral stem in a compromised femur with a supplementary cortical strut allgraft is safe and provides satisfactory clinical and radiological outcomes.

Use of Cortical Strut Allograft After Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty.

BACKGROUND: Cortical strut allografts restore bone stock and improve postoperative clinical scores after revision total hip arthroplasty (THA). However, use of a cortical strut allograft is implicated in delayed healing of an extended trochanteric osteotomy (ETO). To date, there are no reports directly comparing ETO with or without cortical strut allografts. METHODS: We reviewed prospectively gathered data on 50 revision THAs performed from 2004-2014 using an ETO. We compared the demographic, radiological, and clinical outcome of patients with (16 hips) and without (34 hips) cortical strut allograft after an ETO. RESULTS: There were no significant differences in Western Ontario McMaster Universities Osteoarthritis Index or Harris Hip Score between the ETOs with and without a cortical strut allograft. Fifteen of the ETOs (94%) with a cortical strut allograft and 31 of the ETOs (91%) without a cortical strut allograft were in situ at final follow-up (P = 1.000). A higher proportion hips with cortical strut allograft (100%, 16 patients) had preoperative Paprosky grade bone loss more than IIIA compared to those without allograft (29%, 10 patients) (P < .001). There were no differences in femoral stem subsidence (P = .207), alignment (P = .934), or migration of the osteotomized fragment (P = .171). Fourteen of the ETOs (88%) in patients with cortical strut allograft united compared to 34 ETOs (100%) in patients without allograft (P = .095). CONCLUSION: Our study shows that the use of cortical strut allograft during revision THA with ETO does not reduce the rate of union, radiological or clinical outcomes.

Treatment of Secondary Osteonecrosis of the Knee With Local Debridement and Osteoprogenitor Cell Grafting.

Secondary osteonecrosis of the knee (SOK) affects young individuals with chronic diseases and corticosteroid use. We report a series of young patients in whom the osteonecrotic lesion was openly debrided, and concentrated bone marrow osteoprogenitor cells (OPCs) harvested from the iliac crest were placed in the defect. Twelve patients (fourteen knees) have undergone debridement and grafting of distal femoral osteonecrotic lesions. Age at surgery averaged 23 years. Follow-up averaged 5 years. None of the patients have undergone further surgery, or were taking medications for ipsilateral knee pain. Knee Society Score and Knee Function Score averaged 87 and 85 respectively. The technique of open debridement and osteoprogenitor cell grafting for SOK is relatively simple, efficacious, has low morbidity, and does not preclude future interventions.

Polyethylene wear and osteolysis is associated with high revision rate of a small sized porous coated THA in patients with hip dysplasia.

The outcome of 25 primary THAs in patients with hip dysplasia using the AML Bantam femoral stem (DePuy) is reported. Age at operation averaged 43 ± 10 years. Twenty-two of 25 stems were cementless. All cementless acetabular components had conventional or cross-linked polyethylene and screws. Follow-up averaged 11 ± 5 years (range 4-18). Four cementless stems were revised after 3, 4, 8, and 9 years; 2/3 cemented stems were revised at 8 and 18 years. Femoral revisions demonstrated extensive conventional polyethylene wear, periprosthetic osteolysis and loosening. Five entire cups were revised for wear and loosening; four liners were replaced. Harris Hip Scores for patients with retained stems went from 43 ± 12 to 85 ± 13. High revision rates with the proximally porous coated Bantam stem are due to loss of fixation, often associated with polyethylene wear and osteolysis.

Outcome of primary total hip arthroplasty in Charnley Class C patients with juvenile idiopathic arthritis: a case series.

The outcome and complications of 37 primary total hip arthroplasties by one surgeon in 24 patients with Charnley Class C juvenile idiopathic arthritis with up to 19.6 years follow-up are reported. Twenty-six femoral components were cementless; all acetabular components were cementless with screws. Age at operation averaged 22.6 years. Two patients (3 hips) have died. Twelve hips in 9 patients have failed. Six cementless acetabular components with conventional polyethylene were revised because of osteolysis after 5.5 to 14.5 years. All 3 cementless C2 femoral stems with minimal porous coating failed. One of eight cemented AML Bantam stems loosened at 3.5 years; 2 of 23 cementless AML Bantam stems loosened at 9.5 and 19.6 years. Pain relief and functional improvement are dramatic after total hip arthroplasty in juvenile idiopathic arthritis; however, the long-term outcome is guarded.

Cementless femoral prostheses cost more to implant than cemented femoral prostheses.

UNLABELLED: Prosthetic cost contributes greatly to the overall expense of THA. A key question, therefore, in the selection of implant technique is whether any price difference exists between a cementless and a cemented femoral prosthesis. We evaluated the price difference between the most commonly used cemented and cementless femoral stems at three high-volume academic medical centers. Each hospital's costs for prostheses from the manufacturers were recorded. The average cost of implanting a cementless femoral prosthesis was $296 more than the average cost of implanting a cemented femoral stem, even with the additional expense of two batches of bone cement and the accessories commonly used to achieve a third-generation cementing technique. The price difference was less variable if the cost of the prostheses from only the primary implant supplier for each institution was considered. As the number of THAs performed per year continues to escalate, implantation of a cemented femoral component remains an attractive method of fixation from an economic standpoint. LEVEL OF EVIDENCE: Level III, economic and decision analysis. See the Guidelines for Authors for a complete description of levels of evidence.